The aims of this research proposal are to provide a definitive answer to the question of whether formal musical training is associated with enhanced perception of sound. Musicians have been reported to possess enhanced auditory processing of sounds both in quiet and in noise ? a result of processes that may begin as early in the auditory pathway as the cochlea itself. These enhancements may underlie improved abilities to understand speech-in-noise, and because of their profound implications, these studies have generated tremendous interest. However, many of the conclusions were based on studies that had i) relatively few participants, ii) mostly adult participants and iii) no assessment of audiometric or cochlear function in the extended high-frequency (EHF) ranges. These proposed experiments are aimed to remedy these deficiencies by recruiting 150 youth musicians, and assessing both audiometric and cochlear EHF regions. Interestingly, even in people with clinically normal hearing thresholds there are differences in hearing in noise abilities. In fact, while there is no clear relationship between normal standard thresholds (0.25-8kHz) and hearing in noise abilities, there is a proposed relationship between extended high-frequency (EHF) hearing thresholds (8-20 kHz) and improved hearing in noise abilities. In addition to audiometric EHF thresholds, cochlear outer hair cell health can also be assessed non-invasively using distortion-product otoacoustic emissions (DPOAEs) both in the standard and EHF frequency ranges. As mentioned early, most previous studies have sorted their adult participants into ?musicians? or ?non- musicians? based on years of musical training. Our laboratory has recently shown (in both children and adults) that musical aptitude and musical training significantly predict hearing-in-noise abilities. Our hypothesis is that this `musician advantage' in auditory processing is related to both EHF cochlear function and musical aptitude. For both aims, we will recruit ~150 youth (11-18 years) who are students at The Hochstein School as well as other area youth musicians. The Hochstein School enrolls ~ 715 students/year in this age range in their classes and ensembles, providing a natural recruitment platform to assess these behavioral and physiological measures. The specific aims are to investigate whether the `musician advantage' in auditory processing is related to i) EHF audiometric and cochlear function and ii) musical aptitude. Information gained from these studies in youth musicians will provide a rigorous assessment of whether the `musician advantage' in auditory processing exists for all types of sound, and if this advantage is related to musical aptitude, musical training, and EHF cochlear health. We will also be examining what extent music and speech hearing-in-noise abilities overlap, and will be establishing norms and outcome measures that can be used to assess future music-based interventions.